Virgin Mobile FreeFest, a routinely great music festival made even greater by free tickets, has just had its 2013 lineup revealed. Take a look, and remember – this is free.

Robin Thicke and Icona Pop will be joined by many others, including Vampire Weekend, at the Merriweather Post Pavilion in Columbia, Maryland on September 21 for Virgin Mobile FreeFest 2013. Of course, getting free tickets isn’t going to be easy, unless you’re a Virgin Mobile customer or you’ve been to the event before. Those people, along with Facebook friends and Twitter followers of Virgin Mobile (which is easy enough to pull off, no?), will get in on the ‘presale’ at noon (Eastern) on August 8 – basically, granted early access to tickets. Everyone else will have to hit ticketfly.com at noon (Eastern) on August 9 and be really, really fast at entering forms online. Good luck – last year, 50,000 tickets went out and were gone in minutes.

If you get there, you will want to chip in some money, though – donations and money made on the festival grounds will go towards keeping the Sasha Bruce RE*Generation House running in Washington, D.C., a youth homeless shelter. In fact, the lineup this year was announced by a huge mural being put up on the side of the house, identical to the poster you see above. It will also be possible to chip in money by purchasing FreeFest Freemium packages, which include a ticket, a t-shirt, and a souvenir cup – $10 from that package will go towards operating costs for the shelter.